What - and how - you do it will also depend on who/what the project is for.
I like the look of needleturn applique. The little bit I did of it was enjoyable, even if it took me quite a while to do it. I do recommend going to a class for it - it's easier to understand if it's being demonstrated than by trying to learn from a book.
Applique designs can be very simple and largish (easy to do) - to very complex and tiny (harder to do) - no matter what the method.